package com.wc.alorithm_luogu._二分.P1678_烦恼的高考志愿;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.StringTokenizer;

/**
 * @Author congge
 * @Date 2024/3/17 10:47
 * @description https://www.luogu.com.cn/problem/P1678
 */
public class Main {
    /**
     * 思路：
     * 二分找答案
     */
    static FastReader sc = new FastReader();
    static PrintWriter out = new PrintWriter(System.out);
    static int N = 100010;
    static int[] a = new int[N];
    static int n, m;

    public static void main(String[] args) {
        n = sc.nextInt();
        m = sc.nextInt();
        for (int i = 1; i <= n; i++) a[i] = sc.nextInt();
        Arrays.sort(a, 1, n + 1);
        long res = 0;
        for (int i = 1; i <= m; i++) {
            int x = sc.nextInt(), l = 1, r = n;
            int minv = 1000000;
            while (l < r) {
                int mid = l + r >> 1;
                minv = Math.min(minv, Math.abs(a[mid] - x));
                if (a[mid] >= x) r = mid;
                else l = mid + 1;
            }
            res += Math.min(minv, Math.abs(a[l] - x));
        }
        out.println(res);
        out.flush();
    }
}


class FastReader {
    StringTokenizer st;
    BufferedReader br;

    FastReader() {
        br = new BufferedReader(new InputStreamReader(System.in));
    }

    String next() {
        while (st == null || !st.hasMoreElements()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return st.nextToken();
    }

    int nextInt() {
        return Integer.parseInt(next());
    }

    String nextLine() {
        String s = "";
        try {
            s = br.readLine();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return s;
    }

    long nextLong() {
        return Long.parseLong(next());
    }

    double nextDouble() {
        return Double.parseDouble(next());
    }

    // 是否由下一个
    boolean hasNext() {
        while (st == null || !st.hasMoreTokens()) {
            try {
                String line = br.readLine();
                if (line == null)
                    return false;
                st = new StringTokenizer(line);
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return true;
    }
}
